U.S. Pat. No. 4,252,768 to Perkins, et al. discloses abrasion resistant nozzles fabricated by distributing hard refractory metal carbides in a binary solid solution of a ceramic oxide and silicon nitride, preferably a ternary solid solution of a ceramic oxide, silicon nitride and aluminum nitride.
U.S.S.R. Pat. No. 537,986 to Gnesin discloses a ceramic material containing silicon nitride, metal carbide, and magnesium oxide or aluminum oxide, being exceptional in a way that, in order to increase the hardness and wear resistance, it contains as a form of metal carbide, titanium carbide.
In general, wear resistance of a tool depends upon both its resistance to abrasion wear (defined to a great extent by hardness and fracture toughness) and its resistance to chemical or diffusional wear. The wear mode of the tool depends upon the nature of the workpiece. In machining short-chipping materials such as gray cast iron, for example, tool wear is controlled predominanlty by abrasion wear resistance, while in the machining of long-chipping materials such as steel, resistance to chemical wear becomes more important.
A wide variety of silicon nitride based materials containing aluminum oxide and other additional oxides constitute a group of modified silicon aluminum oxynitrides. These materials have relatively low hardness which limits their usefulness as cutting tool materials.